Identification of drought-induced microRNAs in rice.

MicroRNAs (miRNAs) are a large new class of small non-coding RNAs. To date, hundreds of microRNAs have been identified in plants. MicroRNAs play important roles in post-transcriptional gene regulation by targeting mRNAs for cleavage or repressing translation. To better understand microRNA function, we have used an oligonucleotide microarray to monitor rice (Oryza sativa) microRNA expression profile under drought stress. Two drought-induced microRNAs were identified. Furthermore, miR-169g was confirmed as the only member induced by drought among the miR-169 family and the induction of miR-169g was more prominent in roots than in shoots. Sequence analysis revealed occurrence of two proximate DREs (dehydration-responsive element) in the upstream of the MIR-169g, suggesting that miR-169g expression may be regulated directly by CBF/DREBs.